"I" for Claudius (3)
I believe the answer is:
ego
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">i for claudius</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this in another clue)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for ego that I've seen before include "Sense of self, conceit" , "Conscious mind" , "One's self-image" , "See 21 Down" , "Inner self" .)